The parabola opens upward if a > 0
it opens downward if a < 0.
Axis of Symmetry
The axis of symmetry is the vertical line -b/2a.
Y- intercept
the y-intercept is c.
Vertex
The vertex is the point ( -b/2a,f (-b/2a)
Example :
f(x) = x2 - 4x + 6.
a is positive so the parabola opens upward.
to find the axis of symmetry substitute -4 for b and 1 for a
the axis of symmetry is the line x= 2.
the vertex lies on the axis of symmetry so the x coordinate is 2
the y-coordinate is the value of th function at this x-value, or f(2)
the vertex is (2,2).
The parabola opens upward if a > 0
it opens downward if a < 0.
The axis of symmetry is the vertical line -b/2a.
the y-intercept is c.
The vertex is the point ( -b/2a,f (-b/2a)
Example :
f(x) = x2 - 4x + 6.
a is positive so the parabola opens upward.
to find the axis of symmetry substitute -4 for b and 1 for a
the axis of symmetry is the line x= 2.
the vertex lies on the axis of symmetry so the x coordinate is 2
the y-coordinate is the value of th function at this x-value, or f(2)
the vertex is (2,2).
because c = 6 the y-intercept is 6.